Those two cards are not the same. The reason the ATI 6970 is $150 cheaper is because the equivalent Nvidia card is the 570 not the 580. I have a 6970 and it's getting the job done for my 5 boxing. You could buy the 580 which is a little more powerful than the 6970 or you can go for broke with the ATI 6990 or Nvidia 590 which are both dual processor cards. My personal taste is for ATI. Over the years they have been more reliable to me and have always had the best picture vs Nvidia. I have had Nvidia cards die on me and the picture never looked as good as my ATI's. If I had money to waste I would buy the 6990 otherwise go for the mid range 6970. Either way you go all the cards are quality. I still have my doubts about Nvidia though.